Photovoltaic module, photovoltaic module array, photovoltaic system, and method of detecting failure of photovoltaic module

ABSTRACT

The present invention provides a photovoltaic module comprising a photovoltaics and a signal generation means for generating a signal by application of a voltage, wherein the photovoltaics and the signal generating means are connected in parallel and the voltage is a voltage output by the photovoltaics which is connected in parallel with at least the signal generating means, thereby enabling detection of and detect a failed photovoltaic module, regardless of the structure of a photovoltaic module array or the failure mode of the photovoltaic module.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photovoltaic module, a photovoltaicmodule array, a photovoltaic system (photovoltaic power generationapparatus), and a method of detecting failure of a photovoltaic module.

2. Related Background Art

With the recent spreading use of photovoltaic modules, there is arapidly growing demand for photovoltaic modules suitable for use inmedium-scale electric power systems installed outdoors, particularly inthe personal houses. Generally, in the case of using the photovoltaicmodule for electric power generation, a plurality of the photovoltaicmodules are connected in series (hereinafter, referred to as “string”)for generating a voltage not smaller than a certain value, and aplurality of the strings are connected in parallel to form aphotovoltaic module array.

FIG. 29 is a circuit diagram showing the constitution of a conventionalphotovoltaic module. In FIG. 29, there are shown a photovoltaic module1, a photovoltaics 1 a, and a bypass diode 1 b connected parallel to thephotovoltaics 1 a. When a shadow is partly formed on the photovoltaicmodule 1 thereby increasing the electrical resistance of thephotovoltaics 1 a and causing the application of voltage generated inother modules within the string as an inverse bias to the module 1(hereinafter, referred to as “partial shadow”), the bypass diode 1 bprevents the application of an inverse bias to the photovoltaics 1 a inthe photovoltaic module 1 thereby preventing the damage of thephotovoltaic cell. Also, when a photovoltaic module which was part ofthe photovoltaic module array exhibited abnormal output, it was usuallynecessary, for detecting the position of the failure, to check whetherthe electrical output is normal in each string, then to interrupt theoperation of the photovoltaics-photovoltaic system and to measure theelectrical output of each photovoltaic module constituting the string byutilizing the output terminals of each photovoltaic module.

However, since the output terminals are usually provided on the backsurface (a surface opposite to a light incident surface) of thephotovoltaic module, it was very difficult to locate a failure positionby using the output terminals after the installation of the photovoltaicmodule. On the other hand, if terminals for inspection are provided ineach of the modules in such a way that they are exposed to the exterior,they may cause leakage of electricity or danger of electrical shock,thereby causing reliability problems. For these reasons, terminals forinspection were not provided. Consequently, for locating the failedphotovoltaic module in a photovoltaic module array, the current flowedin the wiring of the photovoltaic module array is typically measuredutilizing a clamping ampere meter.

It is preferable in practical use to have a photovoltaic module providedwith current detecting means not exposed to the exterior in order tolocate a failed position. An example of such a photovoltaic moduleincludes the photovoltaic module shown in FIGS. 30A and 30B, asdisclosed in the Japanese Patent Application Laid-Open No. 6-125105 andthe photovoltaic module shown in FIG. 31, as disclosed in the JapanesePatent Application Laid-Open No. 9-148613. In FIGS. 30A and 30B,reference characters 1 c and 1 d indicate magnetic field generatingmeans, and in FIG. 31 reference character 1 e indicates light emittingmeans. In the photovoltaic module shown in FIG. 30A, a current flows ina bypass diode 1 b to generate a magnetic field by the magnetic fieldgenerating means 1 c. The photovoltaic module shown in FIG. 30B is soconstructed that by the electromotive force generated by thephotovoltaics 1 a, an operation current flows into the magnetic fieldgenerating means 1 d to generate a magnetic field. The photovoltaicmodule shown in FIG. 31 is so constructed that a current flows into thebypass diode 1 b to turn on the light emitting means 1 e. The currentdetecting means shown in FIG. 30B utilizes an operation current c1generated during the operation of the photovoltaics 1 a, while thecurrent detecting means shown in FIGS. 30A and 31 utilize a current c2flowing into the bypass diode 1 b when the voltage of the photovoltaics1 a is lowered.

However, the conventional method of detecting failure of a photovoltaicmodule array has the following problems. First, when the photovoltaicsfails, a current flowing into the bypass diode is generated only whenthe failure of the photovoltaics is an open circuit failure, and thismethod cannot be applied to short circuit failure. Second, the failuremay not be detected in some cases, depending on the configuration of thephotovoltaic module array. This problem becomes more conspicuous whenthe photovoltaic module array is equipped with a blocking diode forblocking a reverse current.

An open circuit failure means a failure such as an open circuit of thephotovoltaic cell itself constituting the photovoltaics, or, in the caseof plural photovoltaic cells constituting the photovoltaics, a failuresuch as breaking of a wiring connecting such photovoltaic cells.

Also, a short circuit failure means a failure such as a short circuit ofthe photovoltaic cell itself constituting the photovoltaics (includingpartial short circuit of the photovoltaic cell itself, the same isapplied hereinafter), or, in the case of plural photovoltaic cellsconstituting the photovoltaics, a failure such as the short circuit ofthe wiring connecting such photovoltaic cells.

Both the open circuit failure and the short circuit failure are modes offailure, and these failure states (modes) are referred to as the opencircuit failure mode and the short circuit failure mode, respectively.

The above two problems will be further explained with reference to FIGS.32A to 34B. FIGS. 32A and 32B show the cases of a short circuit failureof the photovoltaics 1 a in the photovoltaic module. In such situation,regardless of the failure state, a current 2 flows into the failuresignal generating means D1 for detecting the failure by the “absence” ofthe operation current of the photovoltaics 1 a. On the other hand, evenin the case of a failure state, the current 2 does not flow into thefailure signal generating means D2 for detecting the failure by the“presence” of the current flowing into the bypass diode 1 b.Distinguishing the failure state from the normal state is not possiblein either case, and the failed photovoltaic module in the string cannotbe detected. FIGS. 33A and 33B show examples of the photovoltaic modulearray constituted by connecting plural strings in parallel. FIG. 33Ashows the state in the normal operation, while FIG. 33B shows the statein the failure state. Reference character 3 indicates a photovoltaicmodule array, and 3 c indicates blocking diodes for preventing lossresulting from the reverse current generated in the case of generating avoltage difference. In such a configuration, when a photovoltaic module1A constituting a part of a string 3 a fails and reaches an open state,the operation current 2 does not flow through the string 3 a at all, asshown in FIG. 33B, if the sum of open circuit voltages Voc2+Voc3generated in other photovoltaic modules 1B and 1C is lower than the sumof operation voltages V4+V5+V6 of the string 3 b. In other words, thereis obtained a state that a current does not flow into all the bypassdiodes and the photovoltaics constituting the string 3 a. Consequently,it is not possible to detect the failed photovoltaic module in thestring 3 a.

FIGS. 34A and 34B are circuit diagrams showing an example of thephotovoltaics module array formed by connecting in series a plurality ofparallel members 3 e of the photovoltaics. FIG. 34A shows the state inthe normal operation, while FIG. 34B is an equivalent circuit diagramshowing a failure state. In FIG. 34A, I1+I2 indicates the operationcurrent 2 in a normal operation. Even when a photovoltaic module 1D isdamaged to generate an open circuit failure as shown in FIG. 34B, if theload current I1′+I2′ is not larger than the operation current of thenon-failed photovoltaic module 1E, reverse bias is not applied to thefailed photovoltaic module 1D at all, so that no current flows into thebypass diode in such module. Consequently, the failure cannot bedetected by the type means of detecting the failure by the currentflowing into the bypass diode.

It is possible to locate a failure point by detecting the operationcurrent of the photovoltaics by employing the constitution as shown inFIG. 30B. However, since the signal generating means 1 d such as themagnetic generating means is connected in series to the photovoltaics,the almost amount of the operation current of the photovoltaics flowedinto the signal generating means almost the all amount of the operationcurrent of the signal generating means was not small, and this lossbecomes a large value which is not negligible particularly in alarge-area photovoltaic module of a large current.

SUMMARY OF THE INVENTION

The present invention has been accomplished in consideration of theabove-described problems in the prior art. An object of the presentinvention is to provide a photovoltaic module, a photovoltaic modulearray, a photovoltaic system and a method of detecting a failedphotovoltaic module, wherein a failure is detected by locating thefailed photovoltaic module, regardless of the constitution of thephotovoltaic module array and the failure mode of the photovoltaicmodule.

Namely, a photovoltaic module of the present invention comprises aphotovoltaics and a signal generating means for generating a signal byapplication of a voltage, wherein the photovoltaics and the signalgenerating means are connected in parallel and the voltage is a voltageoutputted by at least the photovoltaics which is connected in parallelwith the signal generating means.

The photovoltaic module of the present invention also comprises aphotovoltaics and a discrimination means for generating a signal byapplication of a predetermined voltage, wherein the discrimination meansincludes a signal generating means for generating a signal in responseto a signal generated by the discrimination means, the photovoltaics andthe discrimination means are connected in parallel, and the voltage is avoltage outputted by at least the photovoltaics which is connected inparallel with the discrimination means.

The photovoltaic module of the present invention further comprises aphotovoltaics and a signal generating means for generating a signal byapplication of an electrical power, wherein the photovoltaics and thesignal generating means are connected in parallel and in series.

The photovoltaic module of the present invention further comprises aphotovoltaics and a discrimination means for generating a signal byapplication of a predetermined electric power, wherein thediscrimination means includes a signal generating means for generating asignal in response to a signal generated by the discrimination means,and the photovoltaics and the discrimination means are connected inparallel and in series.

The photovoltaic module comprises a single photovoltaic cell, a stringcomposed of a plurality of photovoltaic cells connected in series, or aparallel member composed of a plurality of the photovoltaic cellsconnected in parallel (the same meaning of the photovoltaic module isapplied hereinafter).

The signal generating means is preferably a light emitting means, amagnetic field generating means, an electric field generating means, amechanical displacement generating means, a color development means or acombination thereof.

The signal generating means preferably includes a switching means.

The photovoltaic module preferably further comprises a bypass diode; thephotovoltaics, the signal generating means and the bypass diode arepreferably connected in parallel.

The photovoltaic module is preferably integrated with a constructionmaterial.

The photovoltaic module integrated with the construction materialpreferably further is integrated with a roof panel member.

The signal generating means is preferably provided in the roof panelmember.

The photovoltaic module array of the present invention comprises theabove photovoltaic module.

In the photovoltaic module array, a wiring for mutually electricallyconnecting the above photovoltaic modules is preferably provided at aposition other than a surface of the photovoltaic module.

The photovoltaic module array preferably comprises a blocking diode.

Further, the photovoltaic system of the present invention comprises theabove photovoltaic module array.

Additionally, the method of the present invention of detecting a failedphotovoltaic module comprises obtaining information based on at least anoperation voltage or power of each photovoltaic module and searching forthe presence or absence of failure in each photovoltaic moduleconstituting a photovoltaic module array.

According to the present invention, the signal generating means or thediscrimination means can generate a signal by application of a voltageor a power outputted by at least the photovoltaics which is connected inparallel with one of the signal generating means and the discriminationmeans. Therefore, it is possible to detect a failure, regardless of thefailure mode of the photovoltaic module and the constitution of thephotovoltaic module array, and to locate the failed cell module. Namely,since a closed circuit is formed by the signal generating means, thediscrimination means and the photovoltaics connected in parallel tothese means, for example, in the case of generating a failure in a partof the string of the photovoltaic module, the photovoltaics in theclosed circuit other than the failed part operate. Therefore, even whenthe failure is an open circuit failure or a short circuit failure, it ispossible to discover failure generation and locate the failedphotovoltaic module.

The open circuit failure and the short circuit failure can be alsodiscriminated by the constitution of the signal generating means.

Further, since the signal generating means or the discrimination meansis connected in parallel to the photovoltaics (when the photovoltaicmodule has a bypass diode, since the photovoltaics, the bypass diode andthe signal generating means or the discrimination means are connected inparallel), the full amount of operation current does not necessarilyflow into the signal generating means or the discrimination means.Therefore, it is possible to remarkably prevent power loss in the signalgenerating means or the discrimination means.

Furthermore, in the case where no discrimination means is used, thesignal generating means analogically generates signals (strong or weaksignal). In the case where discrimination means is used in addition tothe signal generating means, the discrimination means generates signalsby application of a predetermined voltage or power, and the signalgenerating means generates a signal; and then in response to thissignal, the signal generating means generates another signal, namely thesignal generating means digitally generates a signal (ON or OFF signal),whereby it is possible to more easily discriminate whether or not theoutput of a photovoltaic module is good.

Additionally, in order to detect the failed photovoltaic module, thepresent invention does not utilize the terminals used in the prior artfor detecting an output provided at each photovoltaic module, andtherefore the reliability of the photovoltaic module of the presentinvention has been improved in this way.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are constitutional diagrams showing one example of aphotovoltaic module. of the present invention;

FIG. 2 is a circuit diagram showing one example of a voltage signalgenerating means for output in a magnetic field form;

FIG. 3 is a circuit diagram showing one example of a voltage signalgenerating means for output in a displacement form;

FIG. 4 is a circuit diagram showing one example of a voltage signalgenerating means for output in an electric field form;

FIG. 5 is a circuit diagram showing one example of a voltage signalgenerating means for output in a light form;

FIG. 6 is an on diagram showing one example of a solar light powergeneration apparatus employing the photovoltaic module shown in FIGS. 1Aand 1B;

FIGS. 7A and 7B are constitutional diagrams showing one example of aphotovoltaic module of the present invention;

FIG. 8 is a circuit diagram showing one example of a voltagediscrimination means with a constant voltage diode;

FIG. 9 is a circuit diagram showing one example of a voltagediscrimination means with an integrated circuit;

FIG. 10 is a circuit diagram showing one example of a voltagediscrimination means with a timer and a sensor;

FIG. 11 is a circuit diagram showing one example of a voltagediscrimination means with another energy source;

FIG. 12A is a plan view showing a photovoltaic module of the presentinvention, and

FIG. 12B is a schematically perspective view from the cross sectiontaken along the line 12B—12B in FIG. 12A, wherein constitutional membersobservable from the cross section are schematically represented;

FIG. 13 is a circuit diagram of the photovoltaic module shown in FIGS.12A and 12B;

FIG. 14A is a plan view showing one example of a photovoltaic module ofthe present invention,

FIG. 14B is a schematically perspective view from the cross sectiontaken along the line 14B—14B in FIG. 14A, wherein constitutional membersobservable from the cross section are represented, and

FIG. 14C is a partial view within a circle in FIG. 14A;

FIG. 15 is a circuit diagram of the photovoltaic module shown in FIGS.14A, 14B and 14C;

FIG. 16A is a plan view showing one example of the photovoltaic moduleof the present invention, and

FIG. 16B is a schematically perspective view from the cross sectiontaken along the line 16B—16B in FIG. 16A, wherein constitutional membersobservable from the cross section are schematically represented;

FIG. 17 is a circuit diagram of the photovoltaic module shown in FIGS.16A and 16B;

FIG. 18 is a perspective view of a photovoltaic module integrated with aconstruction material which is formed by using the module shown in FIGS.16A and 16B;

FIG. 19 is a cross-sectional view showing the state of installation ofthe photovoltaic module shown in FIG. 18;

FIG. 20 is a view showing the state of installing the photovoltaicmodule, shown in FIG. 18 on a roof surface;

FIG. 21 is a block diagram showing the constitution of a solar powergeneration apparatus composed of the photovoltaic module shown in FIG.18;

FIG. 22A is a plan view showing one example of the photovoltaic moduleof the present invention, and

FIG. 22B is a schematically perspective view from the cross sectiontaken along the line 22B—22B in FIG. 22A, wherein constitutional membersobservable from the cross section are represented;

FIG. 23 is a circuit diagram of the photovoltaic module shown in FIGS.22A and 22B;

FIG. 24 is a perspective view showing one example of a roof panel with aphotovoltaic module which is formed by using the photovoltaic moduleshown in FIGS. 22A and 22B;

FIG. 25 is a view showing the state of installation of the roof panelwith a photovoltaic module shown in FIG. 24;

FIG. 26 is a block diagram showing the constitution of the roof panelshown in FIG. 24;

FIG. 27 is a perspective view showing one example of the constitution ofan output terminal box shown in FIG. 26;

FIG. 28 is a block diagram showing the constitution of a solar lightpower generation apparatus composed of the roof panel with thephotovoltaics shown in FIG. 24;

FIG. 29 is a block diagram showing the constitution of a conventionalphotovoltaic module;

FIGS. 30A and 30B are circuit diagrams showing a known example in whichthe photovoltaic module shown in FIG. 29 is provided with a currentdetecting means;

FIG. 31 is a view showing another known example in which thephotovoltaic module shown in FIG. 29 is provided with a currentdetecting means;

FIGS. 32A and 32B are circuit diagrams showing the state of thephotovoltaics failed by a short circuit failure;

FIGS. 33A and 33B are circuit diagrams showing one example of thephotovoltaic module array formed by connecting a plurality of strings ofphotovoltaic modules in parallel; and

FIGS. 34A and 34B are diagrams showing a constitutional example andfunction of a photovoltaic module array formed by connecting in seriesphotovoltaic modules connected in parallel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[Embodiment 1]

FIG. 1A shows the circuit constitution of a photovoltaic module of thepresent invention. In FIG. 1A, reference numeral 12 indicates aphotovoltaic cell; 13, a bypass diode; and 14, a voltage signalgenerating means; which are integrally constructed as a photovoltaicmodule 11. The voltage signal generating means may be replaced by apower signal generating means 15, as shown in FIG. 1B. These componentswill be explained in the following.

(Voltage Signal Generating Means)

The voltage signal generating means is a signal generating means forgenerating a signal by application of a voltage. In consideration of theenergy loss, the signal generating means preferably is a magnetic fieldgenerating means, an electric field generating means, a mechanicaldisplacement generating means, a color development means or a lightemitting means. It may output a signal only when light or magnetic fieldis applied to a specified portion of the photovoltaic module 11, byusing a switching means for closing or opening a circuit with light ormagnetic field. (The switching means preferably is a lead switch whichis operated with a magnetic field.)

FIG. 2 is a circuit diagram showing one example of the voltage signalgenerating means 14 for output in a magnetic field form. In this case,as the voltage signal generating means 14, a magnetic field generatingmeans is used which is provided with a resistor 21 and a coil 22 forgenerating a magnetic field. The magnetic field can be measured with amagnetic needle or a Hall element. The resistor 21 may be omitted, butby series connection with the coil 22, it is possible to suppress theamount of a current flowing into the coil 22, thereby furthersuppressing the power consumption therein. Since it is not necessary toinstall the magnetic field generating means at a position where themeans can be visually confirmed, the magnetic field generating means hasexcellent features such as ease of installation, easy positive andnegative output, or the like.

In the normal operation of the photovoltaics 12 shown in FIGS. 1A and1B, the voltage outputted therefrom is applied in a direction from theresistor 21 to the coil 22, whereby a current flows in such direction.Thus, the coil 22 generates a magnetic field according to the directionof such current flow. For the purpose of simplicity, the directions ofsuch current and such magnetic field are taken as positive. In the caseof an open circuit failure of the photovoltaics 12, there is no outputfrom the photovoltaics 12, so that a current in the negative directionflows in the coil 22 and the bypass diode, whereby a magnetic field ofthe negative direction is generated. In a complete short failure of thephotovoltaics 12, the current scarcely flows in the voltage signalgenerating means 14 and naturally the coil 22, so that the magneticfield is not generated. In a partial short circuit failure of thephotovoltaics 12, a current of the positive direction flows in the coil22 to generate a magnetic field of the positive direction, which ishowever weaker than in the case of normal operation of the photovoltaics12, since the output thereof is lowered in comparison with that in thenormal state. It is therefore possible to detect the failure in thephotovoltaic module, to locate the failed photovoltaic module and todistinguish the open circuit failure and the short circuit failure.

FIG. 3 is a circuit diagram showing an example of the voltage signalgenerating means 14 for output in a displacement form. In this case, asthe voltage signal generating means 14, means for generating amechanical displacement is used. Reference numeral 31 indicates apiezoelectric element for generating a strain by application of avoltage. As the strain direction of the piezoelectric element depends onthe direction of the applied voltage, it is possible, as in the case ofthe magnetic field generating means explained in FIG. 2, to detect thefailure in the photovoltaic module, to search out the failedphotovoltaic module and to distinguish the open circuit failure and theshort circuit failure, by the strain direction of the piezoelectricelement 31. In addition to the direction utilization of the mechanicaldisplacement of the piezoelectric element 31, there may also beinternally provided means for amplifying the mechanical displacement.The displacement may also be induced by the repulsive or attractiveforce of the magnetic field. The generated displacement can be measuredby a laser displacement gauge or a strain gauge. In the case of usingthe mechanical displacement generating means, it has the feature ofeasily discriminating signals under strong sunlight.

FIG. 4 is a circuit diagram showing one example of the voltage signalgenerating means 14 for providing output in an electric field form. Inthis case, as the voltage signal generating means 41, an electric fieldgenerating means is used. It is provided with parallel flat plate-shapedelectrodes 41. The electric field generated between the electrodes maybe directly measured by a known measuring method, or the charge inducedbetween the electrodes is measured, for example, by a surface chargemeter. This method utilizing the electric field has an advantage that itis free from energy loss except for the time of measurement.

FIG. 5 is a circuit diagram showing one example of the voltage signalgenerating means 14 for providing output in a light form. In this case,as the voltage signal generating means 14, a light emitting means isused. It is provided with a lead switch 51, a light emitting diode 52and a resistor 53. The resistor 53 may be omitted, but by seriesconnection with the light emitting diode 52, it is possible to suppressthe amount of current flow in the light emitting diode 52, therebyfurther suppressing the power consumption in the diode 52. The leadswitch 51 can be of a type that is opened or closed by application of anexternal magnetic field, for example, by a permanent magnet. Thisvoltage signal generating means 14 has an advantage that it is free fromenergy loss during normal operation, unless the lead switch 51 isactuated by the magnetic field from the outside. Therefore, the voltagesignal generating means 14 is advantageously free from energy lossexcept for the time of detecting failure.

In the normal operation of the photovoltaics 12 shown in FIGS. 1A, 1Band 2, the voltage outputted therefrom is applied in a direction fromthe lead switch 51 to the resistor 53, whereby a current flows in suchdirection and the light emitting diode 52 emits a light. For the purposeof simplicity, the direction of such current is taken as positive. Inthe case of an open circuit failure of the photovoltaics 12, there is nooutput from the photovoltaics 12; therefore, no current flows in thelight emitting diode 52 due to the directional conductivity of thediode, and the light emitting diode 52 does not emit a light, while acurrent flows in the bypass diode 13. In a complete short circuitfailure of the photovoltaics 12, a current scarcely flows in the voltagesignal generating means 14 and naturally the light emitting diode 52,and the diode 52 does not emit a light. Also current scarcely flows inthe bypass diode 13. In a partial short circuit failure of thephotovoltaics 12, a current of the positive direction flows in the lightemitting diode 52 by the directional conductivity of the diode, wherebythe light emitting diode 52 emits a light. On the other hand, no currentflows in the bypass diode 13. The light emission intensity of the lightemitting diode 52 is weaker than in the case of normal operation of thephotovoltaics 12, since the output of the photovoltaics 12 is lowered incomparison with that in the normal state. It is therefore possible todetect the failure in the photovoltaic module and to locate the failedphotovoltaic module. It is also possible to distinguish the open circuitfailure and the short circuit failure by employing a light emittingmeans such as a light emitting diode as the bypass diode 13 or byutilizing the combination of the light emission/turning off of thebypass diode 13 and the light emitting diode 52. In the normal operationof the photovoltaics 12 shown in FIGS. 1A and 1B, the bypass diode doesnot emit light because no current flows therein by the directionalconductivity thereof. On the other hand, the light emitting diode 52emits a light. In an open circuit failure of the photovoltaics 12, acurrent flows in the bypass diode 13, and the diode emits a light. Onthe other hand, the light emitting diode 52 is turned off. In a completeshort circuit failure of the photovoltaics 12, a current scarcely flowsin the bypass diode 13 so that a light is not emitted. Also the lightemitting diode 52 does not emit a light. In a partial short circuitfailure of the photovoltaics 12, no current flows in the bypass diode13, and a light is not emitted therein because of the directionalconductivity thereof. The light emitting diode 52 emits a light weakerthan in the normal operation state of the photovoltaics 12. It is thuspossible to distinguish the open circuit failure and the short circuitfailure by employing a light emitting diode as the bypass diode 13.

The photovoltaic module of the present embodiment is employed, in placeof the photovoltaic module constituting the conventional photovoltaicmodule arrays shown in FIGS. 33A and 34A, to be able to detect thefailure in the photovoltaic module and to locate the failed photovoltaicmodule, since each photovoltaic module has a closed circuit (formed bythe signal generating means and the photovoltaics constituting eachphotovoltaic module). Specifically, in the case of generating an opencircuit failure or a short circuit failure in one of the photovoltaicmodules shown in FIG. 33A, the output is still given from thephotovoltaics in the closed circuit belonging to the non-failedphotovoltaic module, so that the signal generating means connected inparallel to such photovoltaics can operate. It is therefore possible tojudge that failure is absent in the photovoltaic module by a signalgenerated from the signal generating means, and that failure is presentin the photovoltaic module by a weak signal or no signal from the signalgenerating means. Also in the case of generating an open circuit failureor a short circuit failure in one of the photovoltaic modules shown inFIG. 34A, it is possible to detect the failed photovoltaic module in thesame manner as the case of applying the photovoltaic module of thepresent embodiment to the conventional example shown in FIG. 33A, sinceeach photovoltaic module contains the closed circuit.

The voltage signal generating means 14 need not be installed in aspecified position of the photovoltaic module, but can be installed, forexample, even on the back surface of a photovoltaic cell in the case ofthe voltage generating means 14 utilizing the magnetic field.

Additionally, as the voltage signal generating means 14, it is possibleto use the color development means such as a photochromism element or aliquid crystal element, a color of which can be changed by voltageapplication. These elements are preferable in the present inventionbecause their consumptive powers are further smaller than that of thelight emitting means.

(Power Signal Generating Means)

The power signal generating means is a signal generating means forgenerating a signal by application of an electric power, and may bemeans for utilizing the magnetic field of a known electric power meter.

(Bypass Diode)

The bypass diode, 13 may be not only a known, silicon or germanium diodebut also a device having a rectifying function composed of selenium andis required to function on a voltage smaller than a reverse biasdestructing the photovoltaic cell. With respect to the form, it is notlimited to the conventional molded diode. In fact, a diode formed in apart of the photovoltaic cell or a non-molded thin bypass diode hasrecently been developed. The bypass diode 13 is not necessary in thecase where the minimum reverse bias destructing the photovoltaic cell islarger than the reverse bias generated by the partial shadow.

(Photovoltaic Cell)

The photovoltaic cell for constituting the photovoltaics 12 may be oneof the known various photovoltaic cells such as single-crystalline,polycrystalline or amorphous. Also there can be employed as a materialtherefor various semiconductors such as CIS type, CdTe type, GaAs typeor Si type semiconductor. The effect of the present invention is morefully exhibited in the case of a thin film photovoltaics, because thefailure of the short circuit is easily generated. The photovoltaics 12may be connected in series or in parallel by a known technology such aslaser scribing or interconnector. In this case, the signal generatingmeans, the discrimination means described below and the bypass diode maybe provided for each of the photovoltaic cells connected in series orparallel.

(Photovoltaic Module)

The photovoltaic module 11 may be a photovoltaic module not only havingthe conventionally known superstrate structure or sandwich structure,but also having a recently known structure integrated with aconstruction material. There is a photovoltaic module having the lightentrance surface side also utilizing glass or plastics. The presentinvention is not limited to a part of such structures, but when thepresent invention is applied to a photovoltaic module which is installedon an installation surface and which is wired on the back side of themodule, since the voltage detection is difficult in such a structure,the effect of the present invention becomes more noticeable. Also, inthe field of construction material, it is possible to utilize a blockmember comprising a plurality of the above-described photovoltaicmodules provided on a roof panel member, for example, for pre-fabricatedconstruction. This block member is one embodiment of the photovoltaicmodule and, for convenience, is referred to as “a roof panel with aphotovoltaics” hereinafter.

FIG. 6 is a block diagram showing one example of a photovoltaic systemusing the photovoltaic modules described above. Reference numerals601-606 indicate the above-described photovoltaic modules. Thephotovoltaic modules 601-603 constitute the first string while thephotovoltaic modules 604-606 constitute the second string, and outputwirings of these members are guided to a junction box 607 and connectedin parallel therein. Reference numeral 608 indicates terminal tables forconnecting the wiring of the strings; 609, blocking diodes; 610, a DCswitch; and 611, a power control equipment such as an inverter. Thesecomponents will be explained in the following.

(Blocking Diode)

As the blocking diode 609, an already known high-power diode can beused, preferably with a small on-state resistance. The blocking diode609 prevents a reverse current flowing in a string of a low potentialwhen a potential difference is generated among the strings constitutingthe photovoltaic module array, thereby preventing power loss. However,the blocking diode 609 is not an essential component in the presentembodiment, and the photovoltaic system having a constitution withoutthe blocking diode 609 can be operated.

(Junction Box)

The strings can also be connected in parallel on the installationsurface without employing the junction box 607. But for ease ofmaintenance, the junction box 607 is provided, for example, in an indoorposition and therefore the parallel connection is collectively madetherein. The junction box 607 principally contains the terminal tables608 for fixing the output wirings of the strings, the blocking diodes609 and the DC switch 610 for turning off the DC output, for the purposeof inspection of the power controlling equipment.

(Inverter)

The inverter 611 is often called a power conditioner or a power controlequipment, because it has various functions not only of converting a DCcurrent into an AC current, but also of tracing the maximum power pointof the photovoltaics, protecting the connected system, achievingself-controlled operation and the like. Inverters for medium-scalephotovoltaic power generation are already in mass production, so thatsuch inverter is available from various suppliers.

In the present embodiment, the photovoltaic module array is formed byparallel connection of the first and second strings through theblocking-diodes 609, but there can be adopted various constitutions forthe photovoltaic module array. Also in the photovoltaic system, therecan be adopted various constitutions such as the one in which the powercontrolling equipment is connected to a secondary battery.

In the following there will be explained the procedure of detecting thefailure of the photovoltaic module in the case of generating a failurein the photovoltaic system. At first, a string including the failedphotovoltaic module is detected by measuring the voltage at theterminals of the junction box 607 with a voltage measuring instrumentsuch as a tester. Then the inspector climbs up to the installationsurface. The photovoltaic module is switched to the failure detectionmode when it has means for switching to the failure detection mode. Thenthe failed photovoltaic module is detected with various inspectioninstruments or by visual observation. In doing so, the presentembodiment can significantly reduce the inspection work, because it isnot necessary to detach the photovoltaics and expose the outputterminals or to extract a part of the wirings. Also the presentembodiment can improve the maintainability and reliability of theapparatus, since it can cover various failure modes of the photovoltaicmodule.

[Embodiment 2]

FIG. 7A is a constitutional diagram showing one example of aphotovoltaic module of the present invention. In FIG. 7A, referencenumeral 73 indicates a photovoltaics; 74, a bypass diode; 71, voltagediscrimination means; and 72, signal generating means; which areintegrated as a photovoltaic module 75. The voltage discrimination means71 may be replaced by power discrimination means 80 as shown in FIG. 7B.As the photovoltaic module 75, the photovoltaic cell and the bypassdiode 74, the same as those in Embodiment 1 can be used. Othercomponents will be explained in the following.

(Voltage Discrimination Means)

The voltage discrimination means 71 is a discrimination means forgenerating a signal by application of a predetermined voltage, andpreferably has a high input resistance. More specifically, it includes aconstant voltage diode, an FET or a MOS semiconductor device utilizingthe electric field effect, or an electronic circuit combined with aresistor for realizing a high input resistance.

(Power Discrimination Means)

The power discrimination means 80 is a discrimination means forgenerating a signal by application of a predetermined electric power.More specifically, it includes a device for calculating the outputs froma current sensor 76 and a voltage sensor 77 with a knownsemiconductor-based integrated circuit 78. Reference numeral 79indicates a comparator for judging the result of calculation.

(Signal Generating Means)

The signal generating means 72 is a signal generating means forgenerating a signal in response to a signal generated by the voltagediscrimination means 71 or the power discrimination means 80.

The signal generating means 72 is not particularly limited, but ispreferably means driven with a small current. More specifically, itincludes a display element utilizing physical properties such as an LED,a photochromic element, an electroluminescent element or a liquidcrystal element, or a mechanical display element utilizing apiezoelectric element or electromagnetic force of a magnet and a coil.

In the following there will be given a detailed explanation on thevoltage discrimination means 71 and the signal generating means 72.

FIG. 8 shows an example employing a reference diode 83 as the voltagediscrimination means 71 and a resistor 85 and a light emitting diode 84as the signal generating means, which is realized in a simpleconstitution. The resistor 85 may be omitted, but by series connectionwith the light emitting diode 84, it is possible to suppress the amountof a current flowing therein, thereby further suppressing the powerconsumption therein. In the operation state of the photovoltaics 73shown in FIG. 7A, the voltage outputted therefrom is applied in adirection from the light emitting diode 84 to the resistor 85. Thisdirection is taken as positive. The reference diode 83 is so selected asto have a Zenar voltage smaller than the voltage applied to thereference diode 83 in the positive direction under the normal operationstate of the photovoltaics 73. Thus, in the normal operation state ofthe photovoltaics 73, a current flows in the reference diode 83, therebycausing the light emitting diode 84 to emit a light. In a partial shortcircuit failure of the photovoltaics 73, the output of the photovoltaics73 becomes smaller than in the normal operation state. Thus, when thevoltage applied to the reference diode 83 becomes smaller than the Zenarvoltage thereof, the light emitting diode 84 is turned off. In contrastto the signal generating means shown in FIG. 5, which functions in ananalog manner, the present embodiment provides a digital functionbecause the failure is detected by the on/off state of the lightemitting diode 84. In this manner, it is possible to easily judgewhether the output of the photovoltaic module is satisfactory or not.Except for the above point, the method of detecting the failure of thephotovoltaic module and locating the failed photovoltaic module issimilar to that explained in relation to FIG. 5. It is also possible, asexplained in relation to FIG. 5, to distinguish the open circuit failureand the partial short circuit failure by employing a light emittingdiode or the like as the bypass diode 74.

FIG. 9 shows an example employing an integrated circuit formed by theknown CMOS process. The integrated circuit formed by the CMOS processexhibits low power consumption. The signal generating means 72 iscomposed of a magnetic field generating coil 94, while the voltagediscrimination means 71 is composed of a reference voltage generationmeans 95 and a comparator 93. The power for the integrated circuit issupplied from a detecting power source. When a normal voltage isgenerated, a current is supplied to the coil 94 to generate a magneticfield. Though FIG. 9 illustrates the use of plural integrated circuits,it is naturally possible to realize the circuit with a single integratedcircuit.

FIG. 10 shows one example in which control means 104 composed of a timeror a sensor is added to the constitution shown in FIG. 9. In thisconstitution, it is possible to reduce the energy consumed in the signalgenerating means 72 by intermittently turning on a light emitting diode106 therein of the signal generating means 72, in addition, and toprovide a failure detection mode by employing a sensor as the controlmeans 104, and to suppress the energy loss by stopping the power supplyto the signal generation means 72, except for the time of setting thefailure detection mode.

FIG. 11 shows one example in which an external power supply means 115 isadded to the constitution shown in FIG. 9. In this constitution, it ispossible to activate the signal generating means 72 by the externalpower supply means 115 only in the failed state of the photovoltaicmodule, thereby preventing the energy loss in the ordinary operationstate. As the external power supply means 115, it is possible to use anadditional photovoltaics provided for the signal generating means oranother external power source.

When the photovoltaic module of the present embodiment is used in placeof the photovoltaic module constituting the conventional photovoltaicmodule arrays shown in FIGS. 33A and 34A, it is possible to detect thefailure in the photovoltaic module and to locate the failed photovoltaicmodule, since each photovoltaic module has a closed circuit (composed ofthe discrimination means and the photovoltaics constituting eachphotovoltaic module). Specifically, even when an open circuit failure ora partial short circuit failure occurs in one of the photovoltaicmodules shown in FIG. 33A, the output is still given from thephotovoltaics in the closed circuit belonging to the non-failedphotovoltaic module, so that the discrimination means and the signalgenerating means connected in parallel to each photovoltaics can executethe functions thereof. It is therefore possible to judge that failure isabsent in the photovoltaic module of which the signal generating meansgenerates a signal, and that failure is present in the photovoltaicmodule in which the signal from the signal generating means is absent orweak. Also even when an open circuit failure or a partial short circuitfailure occurs in one of the photovoltaic modules shown in FIG. 34A, itis possible to detect the failed photovoltaic module in the same manneras the case of applying the photovoltaic module of the presentembodiment to the conventional constitution shown in FIG. 33A, sinceeach photovoltaic module has the closed circuit.

Accordingly, it is possible to constitute the photovoltaic module arrayor the photovoltaic system in the same manner as Embodiment 1 and torealize the detection of the failed photovoltaic module by the sameprocess. Therefore, also the present embodiment can significantly reducethe inspection work, because it is not necessary to detach thephotovoltaics and expose the output terminals or to extract a part ofthe wirings. Also the present embodiment can improve the reliability ofthe apparatus, since it can cover various failure modes of thephotovoltaic modules.

In the following, the present invention will be clarified further byexamples of a photovoltaic module constitution, a photovoltaic modulearray constitution or a photovoltaic system in a specific manner.

EXAMPLE 1

FIGS. 12A, 12B and 13 are a plan view, a schematically perspective viewand a circuit diagram, respectively, showing a photovoltaic module ofthe present invention. Specifically, FIG. 12A is a plan view showing thestructure of a photovoltaic module of the so-called superstratestructure. FIG. 12B is a schematically perspective view from the crosssection taken along the line 12B—12B in FIG. 12A. FIGS. 12A and 12B showpolycrystalline photovoltaic cells 1201, a protective glass 1202,silicone resin 1203, and a moisture preventing film 1204 consisting of alaminated Tedlar/aluminum foil/Tedlar film. Known vacuum laminatingtechnology can be applied for sealing these materials, thereby easilysealing the photovoltaic cell 1201 for forming the module. Inconsideration of the external appearance, the color of the Tedlar filmwas selected as blue in order to match the color of the polycrystallinephotovoltaic cell. On the surface of the photovoltaic cell 1201, thereis formed a current collecting electrode 1205, and the photovoltaiccells 1201 are connected in series by an interconnector 1206 as shown inFIG. 13 and are guided to an output terminal box 1207 by which theelectrical output is taken out to the exterior.

A bypass diode 1208 for protecting the photovoltaic cells 1201 isprovided in the output terminal box 1207 in this example. There are alsoprovided a lead switch 1209 which is turned on by application of amagnetic field from the exterior, and a voltage signal generating means1210 consisting of a light emitting diode 1212 and a resistor 1213. Adark-colored masking film 1211 is provided, so that the light of thelight emitting diode 1212 can be confirmed even in the daylight.

In the case of detecting the failed photovoltaic module, the inspectionis executed by applying a magnetic field, for example, with a permanentmagnet, to the lead switch 1209 of each installed photovoltaic module.The photovoltaic module is judged normal when the light emitting diode1212 is turned on by application of the magnetic field. The photovoltaicmodule is detected as in failure when the light-emitting amount issmaller than that in an ordinary turn-on state or the light emittingdiode 1212 is not turned on. Each photovoltaic module is completely freefrom electric power consumption in the normal operating state withoutthe application of the magnetic field. Each photovoltaic module can beinstalled by conventionally known various installing methods.

EXAMPLE 2

FIGS. 14A, 14B and 15 show a photovoltaic module of the presentinvention. FIGS. 14A and 14B are respectively a plan view and across-sectional view showing the representative example of aphotovoltaic module having the so-called substrate structure. FIGS. 14Aand 14B show amorphous photovoltaic cells 1401, a reinforcing plate1402, a sealing resin 1403 consisting of a mixture of EVA (ethylenevinyl acetate) resin and a non-woven glass cloth, a transparentpolyethylene film 1404 for insulation between the painted steel plate1402 and the photovoltaic cell 1401, a black polyethylene film 1411 forconcealing a non-power-generating area such as of an interconnector anda diode, and a transparent fluororesin film 1405 for surface protection.This photovoltaic module can be also prepared by sealing thephotovoltaic cells 1401 with the known laminating technology.

On the surface of the photovoltaic cell 1401, there is formed a currentcollecting electrode 1406, and the photovoltaic cells 1401 are connectedin series by an interconnector 1407 as shown in the circuit diagram ofFIG. 15 and are guided to an output terminal box 1409 by which theelectrical output is taken out to the exterior.

A bypass diode 1408 for protecting the photovoltaic cells 1401 isprovided, in this example, for each of the elements 1401. Parallel flatplate-shaped electrodes 1410 are provided for concentrating the electricfield and displaying the voltage by such electric field. FIG. 14C is amagnified partial view of the parallel plate-shaped electrodes 1410. Theelectric field can be read for example by a surface charge measuringdevice for reading the charge accumulated in a space applied with anelectric field or a device for reading a dielectric member such assealing resin distorted by an electric field by a laser beam.

This photovoltaic module is advantageous in that it is completely freefrom electric power consumption during normal operation. Also,conventionally known installing methods can be applied to this example.

EXAMPLE 3

FIGS. 16A and 16B to 21 show one example of the photovoltaic module ofthe present invention. FIG. 16A is a plan view showing a constructionmaterial-integrated photovoltaic module having a substrate constitutionaccording to the present example. FIG. 16B is a schematicallyperspective view from the cross section taken along the line 16B—16B inFIG. 16A. FIGS. 16A and 16B show amorphous photovoltaic cells 1601, apainted construction steel plate 1602, sealing resin 1603 consisting ofa mixture of EVA (ethylene vinyl acetate) resin and non-woven glasscloth, a polyethylene film 1604 for insulation between the painted steelplate 1602 and the photovoltaic cell 1601, and a transparent fluororesinfilm 1605 for surface protection. This photovoltaic module can be alsoformed by sealing the photovoltaic cells 1601 with known laminatingtechnology.

A current collecting electrode 1606 is formed on the surface of thephotovoltaic cell 1601, and the photovoltaic cells 1601 are connected inseries by an interconnector 1607 as shown in the circuit diagram of FIG.17 and are guided to an output terminal box 1609 by which the electricaloutput is taken out to the exterior.

One bypass diode 1608 for protecting the photovoltaic cells 1601 isprovided, in this example, for each element 1601. A black polyethylenefilm 1610 is provided for concealing the non-power-generating area andis provided with a hole 1612 for exposing a voltage detection block1611. As shown in the circuit diagram of FIG. 17, the voltage detectionblock 1611 is an integral unit containing a voltage discrimination means1701 and a voltage signal generation means 1702, and in this example, anintegral unit containing an integrated semiconductor circuit and adisplay device is used.

FIG. 18 is a perspective view showing one example in which the flatpanel type photovoltaic module integrated with the construction materialshown in FIGS. 16A and 16B is formed into a ribbed seam roof member.FIG. 18 shows a lead wire 1801 for taking out the electrical output ofeach photovoltaic module from an output terminal box 1609, and aconnector 1803 for interconnecting the photovoltaic modules by a singleaction.

FIG. 19 is a cross-sectional view showing the case where a ribbed seamroof member integrated with the photovoltaic modules are installed onthe roof. FIG. 19 shows a sheathing roof board 1901, a water-repellentsheet 1902, and a batten 1903 for forming a wiring space between thephotovoltaics and the roof board. The photovoltaic modules are connectedin this space to form strings as shown in FIG. 21, which are connectedin parallel in an indoor junction box 2102. The photovoltaic modules arefixed to the batten 1903 with a two sides-fixing clip, and cappingmembers 1905 are placed thereon to prevent rain damage. FIG. 20 showsone example in which the ribbed seam roof members integrated with thephotovoltaic modules are installed on the surface of a gable roof. FIG.20 also shows a ribbed seam roof member 2001 integrated with thephotovoltaic module and ordinary roof materials 2002, which are used forforming the end portions of the roof and for regulating the standardpower generation capacity of the photovoltaic system.

FIG. 21 is a block diagram of the thus constructed photovoltaic system.FIG. 21 shows photovoltaic modules 2101, a junction box 2102, DCswitches 2103 provided at the side of the photovoltaic modules and usedfor disconnecting the photovoltaic modules 2101 at the time ofreplacement thereof, arresters 2104 for preventing destruction of theapparatus by lightening, blocking diodes 2105, a DC switch 2106 to beused in the case of inspection of the power control equipment, and apower control equipment 2107 by which the present photovoltaic system isconnected to an external system to form a reverse current system.

In the following there will be explained, with reference to FIG. 21, themethod of identifying the failed photovoltaic module. At first, in thedaytime, there is measured the terminal voltage at the input side of theDC switch 2103. As the failure of a photovoltaic module results in adecrease in the terminal voltage, the position of the failed module canbe predicted by locating the string with a lowered voltage. Then theinspector climbs up to the installation surface and confirms, by visualobservation, the display unit of the photovoltaic module which isassumed to have failed. So, the failed module can be located. In thistime, it is necessary to confirm that the photovoltaic modules are freefrom the partial shadow phenomenon.

Although the installation of the photovoltaics on the roof and themaintenance thereof are expensive, this example can facilitate themaintenance work since the failed photovoltaic module can be easilylocated. It is therefore possible to maintain the photovoltaic system inan inexpensive manner. Also high reliability can be realized since thefailure detection means is incorporated into the roof member. There isfurthermore provided an advantage of easy installation, since particularwiring work is not required for failure detection.

EXAMPLE 4

FIGS. 22A and 22B to 28 show one example of the photovoltaic module ofthe present invention. FIG. 22A is a plan view showing one example of aphotovoltaic module integrated with a construction material having asubstrate structure. FIG. 22B is a schematic perspective view from thecross section taken along the line 22B—22B in FIG. 22A. FIGS. 22A and22B show amorphous photovoltaic cells 2201, a reinforcing painted steelplate 2202, sealing resin 2203 consisting of a mixture of EVA (ethylenevinyl acetate) resin and non-woven glass cloth, a polyethylene film 2204for insulation between the painted steel plate 2202 and the photovoltaiccells 2201, and a transparent fluororesin film 2205 for surfaceprotection. This photovoltaic module can be also formed by sealing thephotovoltaic cells with known laminating technology.

On the surface of the amorphous photovoltaic cell 2201, there is formeda current collecting electrode 2206, and the amorphous photovoltaiccells 2201 are connected in series by an interconnector 2207 as shown inthe circuit diagram of FIG. 23 and are guided to an output terminal box2209. The electrical output is taken out from apertures 2208 of thepainted steel plate 2202. Each photovoltaic module is provided, at theends thereof, with two apertures 2208 for plus terminals and an aperture2208 for minus terminal. In this example, a bypass diode 2209 forprotecting the amorphous photovoltaic cells 2201 is provided for eachelement 2201. A black polyethylene film 2210 is provided for concealingthe non-power-generating area. An advantageous feature of this exampleresides in that the above-described photovoltaic module integrated withthe construction material is used as a roof panel as one embodiment ofthe photovoltaic module shown in FIG. 24.

FIG. 26 is a circuit diagram of the roof panel with the photovoltaics2600 of this example. FIG. 26 show a construction material-integratedphotovoltaic module 2601, and an output terminal box 2602 for connectingthe lead wires of the construction material-integrated photovoltaicmodules 2601. FIG. 27 shows an output terminal box 2602. The outputterminal box 2602 consists of a semiconductor integrated circuit 2701constituting the voltage discrimination means, which is means fordetecting the failure and a light emitting diode 2702 constituting thesignal generating means for converting the output signal of theintegrated circuit into light. The roof panel with the photovoltaics2600 is constructed, as shown in FIG. 24, with a roof panel member 2401,the above-mentioned construction material-integrated photovoltaic module2601 which is formed as the ribbed seam roof member, a two-sides fixingclip 2403 and a one-sided fixing clip 2404 for fixing the constructionmaterial-integrated photovoltaic modules 2601 to the roof panel 2401, anoutput terminal box 2602 for connecting the electrical output from theconstruction material-integrated photovoltaic module 2601, and a capmember 2406 for covering the connecting part of the constructionmaterial-integrated photovoltaic modules 2601. The cap member 2406 isprovided with a window 2405 in a portion corresponding to the signalgenerating means 2702 shown in FIG. 27, and the failure of thephotovoltaic module 2601 can be found out through the window 2405.

FIG. 25 shows the state of installation of the roof panel with the solarpanel shown in FIG. 24 on the roof surface. The roof panel with thesolar panel 2600 is hoisted by a housing device 2502 such as a crane andis fixed to a main house 2501 itself to constitute the roof.

FIG. 28 shows a photovoltaic system comprising the roof panel with thephotovoltaics 2600. FIG. 28 shows an arrester 2802, a DC switch 2803 atthe side of the photovoltaics, blocking diodes 2804, a 3-line DC switch2805, a junction box 2806 and an inverter 2807 for connection to theexternal system.

The roof panel with the photovoltaics 2600 of the present exampleprovides a particular effect of promptly installing the photovoltaicseson the roof surface. Also the roof surface after installation appearsthe same as in the case of utilizing the general constructionmaterial-integrated photovoltaic modules. Though the installation andmaintenance of the photovoltaics on the roof were expensive, the presentexample can facilitate the maintenance work because the failed modulecan be easily located. It is thus possible to achieve maintenance of thephotovoltaic system in an inexpensive manner. Since the failuredetection means is pre-assembled within the roof panel 2600 at themanufacturing factory, there is not required any particular wiring workfor failure detection on the roof, so that the installation can beeasily achieved. It is furthermore possible to form a ventilating grooveby positioning the batten 1903 shown in Example 3, between theconstruction material-integrated photovoltaic module 2601 and the roofpanel member 2401, and such configuration allows suppression ofgenerated power loss due to the temperature characteristics of thephotovoltaics, by the cooling effect of the air flowing in such aventilating groove. Such air flow can also be used as the heat sourcefor the building.

As explained in the foregoing, according to the present invention, it ispossible to easily locate the failed photovoltaic module, regardless ofthe failure mode of the photovoltaics. It is thus possible to improvethe efficiency of the maintenance and inspection works.

Also it is possible to increase design freedom of the photovoltaicmodule array, since failure detection is made possible in photovoltaicmodule arrays having various constitutions.

What is claimed is:
 1. A photovoltaic module comprising photovoltaicsand a signal generating means for generating a signal by application ofa voltage, wherein said photovoltaics and said signal generating meansare connected in parallel, the voltage is a voltage outputted by atleast said photovoltaics which is connected in parallel with said signalgenerating means, said signal generating means and said photovoltaicsare provided within a wiring of said photovoltaic module, said signalgenerating means includes a switching means, a circuit of which isclosed or opened with light or magnetic field, and said signalgenerating means outputs a signal only when light or magnetic field isapplied to said switching means.
 2. The photovoltaic module according toclaim 1, wherein said photovoltaics comprises a single photovoltaiccell, a string composed of a plurality of photovoltaic cells connectedin series, or a parallel member composed of a plurality of photovoltaiccells connected in parallel.
 3. The photovoltaic module according toclaim 2, wherein said signal generating means is a light emitting means,a magnetic field generating means, an electric field generating means, amechanical displacement generating means, a color development means or acombination thereof.
 4. The photovoltaic module according to claim 2,further comprising a bypass diode, wherein said photovoltaics, saidsignal generating means and said bypass diode are connected in parallel.5. The photovoltaic module according to claim 2, further comprising aconstruction material integrated with said photovoltaic module.
 6. Thephotovoltaic module according to claim 5, further comprising a roofpanel member integrated with said photovoltaic module.
 7. Thephotovoltaic module according to claim 6, wherein said signal generatingmeans is provided in the roof panel member.
 8. A photovoltaic modulecomprising photovoltaics and a discrimination means for generating asignal by application of a predetermined voltage, wherein saiddiscrimination means includes a signal generating means for generating asignal in response to a signal generated by said discrimination means,said photovoltaics and said discrimination means are connected inparallel, the voltage is a voltage outputted by at least saidphotovoltaics which is connected in parallel with said discriminationmeans, said discrimination means and said photovoltaics are providedwithin a wiring of said photovoltaic module, said signal generatingmeans includes a switching means, a circuit of which is closed or openedwith light or magnetic field, and said signal generating means outputs asignal only when light or magnetic field is applied to said switchingmeans.
 9. The photovoltaic module according to claim 8, wherein saidphotovoltaics comprises a single photovoltaic cell, a string composed ofa plurality of photovoltaic cells connected in series, or a parallelmember composed of a plurality of photovoltaic cells connected inparallel.
 10. The photovoltaic module according to claim 9, wherein saidsignal generating means is a light emitting means, a magnetic fieldgenerating means, an electric field generating means, a mechanicaldisplacement generating means, a color development means or acombination thereof.
 11. The photovoltaic module according to claim 9,further comprising a bypass diode, wherein said photovoltaics, saiddiscrimination means and said bypass diode are connected in parallel.12. The photovoltaic module according to claim 9, further comprising aconstruction material integrated with said photovoltaic module.
 13. Thephotovoltaic module according to claim 12, further comprising a roofpanel member integrated with said photovoltaic module.
 14. Thephotovoltaic module according to claim 13, wherein said discriminationmeans and said signal generating means are provided in the roof panelmember.
 15. A photovoltaic module comprising photovoltaics and a signalgenerating means for generating a signal by application of an electricalpower, wherein said photovoltaics and said signal generating means areconnected in parallel and in series, said signal generating means andsaid photovoltaics are provided within a wiring of said photovoltaicmodule, said signal generating means includes a switching means, acircuit of which is closed or opened with light or magnetic field, andsaid signal generating means outputs a signal only when light ormagnetic field is applied to said switching means.
 16. The photovoltaicmodule according to claim 15, wherein said photovoltaics comprises asingle photovoltaic cell, a string composed of plurality of photovoltaiccells connected in series, or a parallel member composed of a pluralityof photovoltaic cells connected in parallel.
 17. The photovoltaic moduleaccording to claim 16, wherein said signal generating means is a lightemitting means, a magnetic field generating means, an electric fieldgenerating means, a mechanical displacement generating means, a colordevelopment means or a combination thereof.
 18. The photovoltaic moduleaccording to claim 16, further comprising a bypass diode, wherein saidphotovoltaics and said bypass diode are connected in parallel.
 19. Thephotovoltaic module according to claim 16, further comprising aconstruction material integrated with said photovoltaic module.
 20. Thephotovoltaic module according to claim 19, further comprising a roofpanel member to be integrated with said photovoltaic module.
 21. Thephotovoltaic module according to claim 20, wherein said signalgenerating means is provided in the roof panel member.
 22. Aphotovoltaic module comprising photovoltaics and a discrimination meansfor generating a signal by application of a predetermined electricpower, wherein said discrimination means includes a signal generationmeans for generating a signal in response to a signal generated by saiddiscrimination means, said photovoltaics and said discrimination meansare connected in parallel and in series, said discrimination means andsaid photovoltaics are provided within a wiring of said photovoltaicmodule, said signal generating means includes a switching means, acircuit of which is closed or opened with light or magnetic field, andsaid signal generating means outputs a signal only when light ormagnetic field is applied to said switching means.
 23. The photovoltaicmodule according to claim 22, wherein said photovoltaics comprises asingle photovoltaic cell, a string composed of a plurality ofphotovoltaic cells connected in series, or a parallel member composed ofa plurality of photovoltaic cells connected in parallel.
 24. Thephotovoltaic module according to claim 23, wherein said signalgenerating means is a light emitting means, a magnetic field generatingmeans, an electric field generating means, a mechanical displacementgenerating means, a color development means or a combination thereof.25. The photovoltaic module according to claim 23, further comprising abypass diode, wherein said photovoltaics and said bypass diode areconnected in parallel.
 26. The photovoltaic module according to claim23, further comprising a construction material integrated with saidphotovoltaic module.
 27. The photovoltaic module according to claim 26,further comprising a roof panel member integrated with said photovoltaicmodule.
 28. The photovoltaic module according to claim 27, wherein saiddiscrimination means and said signal generating means are provided insaid roof panel member.